ML20244A739
| ML20244A739 | |
| Person / Time | |
|---|---|
| Issue date: | 06/13/1979 |
| From: | Grimes B Office of Nuclear Reactor Regulation |
| To: | Bryan S NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| Shared Package | |
| ML20236N106 | List: |
| References | |
| FOIA-87-724 NUDOCS 7908070039 | |
| Download: ML20244A739 (2) | |
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UNITED STATES f, "c(
NUCLEAR REGULATORY COMMISSION i
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June 13, 1979 j
i MEMCRANDUM FOR:
Samuel E. Bryan, Assistant Director for Field Coordination FROM:
Brian X. Grimes, Assistant Director for Engineering and Projects
SUBJECT:
CLARIFICATION OF STS: AC AND OC DISTRIBUTION
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As requested in your memo dated March 8,1979 (which forsarded J. Streeter's l
memo dated January 29,1979), we have reviewed the STS relative to AC and CC l
electrical power distribution.
In the development of these specific technical l
l specifications, as well as throughout tf.e, entire STS package, it has been our intent that the licensee not be required to assume a snowball effect of the type suggested in J. Streeter's memo.
It has been our intent that l
when an item is addressed in a LCO, the specific Action statement provided i
for that LCO be the governing requirement for continued plant operation.
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I The Action statements in the STS are provided in response to 10 CFR Part 50.36(c)(2) which states in part: "When a lim' ting condition for operation j
of a nuclear reactor is not met, the licensee snall shut down the reactor or follow any remedial action permitted by the technical specification
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until tne condition can ce met".
We believe tit for a relatively short time period (witnin the time limits specified 'n the various STS Action statements) it is usually safer to permit plan operations to continue j
rather than to require initiation of a shutdown transient.
A second concern expressed in J. Streeter's memo was that the STS do not preclude having a diesel generator associated with one AC/DC bus train l
inocerable and concurrently an inoperable battery. in the other DC train.
This scenario was recogni:ed and considered during the develcoment of the l
STS. We do not believe that any further actions are required nor are ar.y i
furtner actions planned at this time since operation in the pesculated l
conditions would oe very ifmited. The Action statement for Specification i
3.3.2.3 permits plant operatir"- to continue for a maximum of 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> ofter l
wnicn tne incperable battery mu.t either ce returned to coerab'.e status or a plant shutdown must be initiited and the unit must oe-in hot standoy within the following 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.
The $110wable Nt of service times soeci#ied
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l in the STS for the AC and DC electri:al power supplies are consistent l
witn the rec 0ctnendations of Regulate,ry Guide 1.93.
1 The tnird concern expressed in J. Streeter's memo was tnat licensees may v0luntarily er.ter technical specification action statements aniated with i
ACandDCdistributionbyclosingtiebr[eakersbetweenreoundantcuses.
In response to this concern, it should be noted that throughout the STS, and typically in the custom technical specifications, the inensee is i
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Salnual E. Bryan June 13, 1979 l
not prohibited from voluntarily entering action statements. We believe it is necessary and desirable to structure the technical specification to permit the operator to exercise judgment within the latitude permitted j
by Technical Specifications.
It should be further noted that during operation in a degraded mode under the provisions of an' action statement, the facility may not be capable of responding to an initiating event plus a concurrent or-subsequent single failure of an active component.
There fore,
the action statements restrict operation in the specified degraded mode l
of operation to a limited period of time.
We are not aware of instances in which licensees have abused the provisions of being able to voluntarily enter Action statements; however, if a licensee should frequently initiate such activities, please bring it to our attention and we will consider further actions on a case basis. Additionally, we would call your attention to Specification 3.0.4 in the STS which prohibits entering an operational mode unless the operability requirements of the limiting condition for operation are satisfied without reliance on the provisions of the associated Action statement.
This prevents startup when the opportunity is available l
to meet the operability requirements without initiating a shutdown transient.
A fourth concern expressed was that the acceptance criteria of 1.200 for the battery specific gravity was overly restrictive.
This item is a plant specific value in the STS and the value of 1.200 was supplied by the applicant / licensee as be!ng the applicable value, in accordance with the recommendations of Regulatory Guide 1.129, for the subject battery.
This value was reviewed by NRR during the preparation of the subject technical specifications and no further actions are considered necessary at this time.
We hace that these coments have resblved the problems you raised.
O. 3rinkman is available for further:clarificati as necessary.
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MNC Brian K. Grimes, Assistant Director i
for Engineering and projects Dfvision of Operating Reactors cc:
V. Stello
- 0. Eisenhut 00R Project Branch Chiefs STS Group Members O. Iondi
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